On Tue, 7 Jan 2025 08:38:43 -0600 Terry Bowman <terry.bowman@xxxxxxx> wrote: > Existing recovery procedure for PCIe uncorrectable errors (UCE) does not > apply to CXL devices. Recovery can not be used for CXL devices because of > potential corruption on what can be system memory. Also, current PCIe UCE > recovery, in the case of a Root Port (RP) or Downstream Switch Port (DSP), > does not begin at the RP/DSP but begins at the first downstream device. > This will miss handling CXL Protocol Errors in a CXL RP or DSP. A separate > CXL recovery is needed because of the different handling requirements > > Add a new function, cxl_do_recovery() using the following. > > Add cxl_walk_bridge() to iterate the detected error's sub-topology. > cxl_walk_bridge() is similar to pci_walk_bridge() but the CXL flavor > will begin iteration at the RP or DSP rather than beginning at the > first downstream device. I'm still holding out for making pci_walk_bridge() do the same and seeing what if anything breaks. Other than that I'm fine with this patch. > > Add cxl_report_error_detected() as an analog to report_error_detected(). > It will call pci_driver::cxl_err_handlers for each iterated downstream > device. The pci_driver::cxl_err_handler's UCE handler returns a boolean > indicating if there was a UCE error detected during handling. > > cxl_do_recovery() uses the status from cxl_report_error_detected() to > determine how to proceed. Non-fatal CXL UCE errors will be treated as > fatal. If a UCE was present during handling then cxl_do_recovery() > will kernel panic. > > Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
